JPH06132509A - Solid-state image sensing device - Google Patents
Solid-state image sensing deviceInfo
- Publication number
- JPH06132509A JPH06132509A JP4280004A JP28000492A JPH06132509A JP H06132509 A JPH06132509 A JP H06132509A JP 4280004 A JP4280004 A JP 4280004A JP 28000492 A JP28000492 A JP 28000492A JP H06132509 A JPH06132509 A JP H06132509A
- Authority
- JP
- Japan
- Prior art keywords
- photoelectric conversion
- signal
- charge transfer
- solid
- unit
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000006243 chemical reaction Methods 0.000 claims abstract description 35
- 239000012535 impurity Substances 0.000 claims abstract description 12
- 238000009792 diffusion process Methods 0.000 claims abstract description 11
- 238000003384 imaging method Methods 0.000 claims description 7
- 230000003287 optical effect Effects 0.000 claims description 6
- 230000006866 deterioration Effects 0.000 abstract description 4
- 229910021420 polycrystalline silicon Inorganic materials 0.000 description 11
- 229920005591 polysilicon Polymers 0.000 description 11
- 239000000758 substrate Substances 0.000 description 10
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 7
- 229910052710 silicon Inorganic materials 0.000 description 7
- 239000010703 silicon Substances 0.000 description 7
- 238000010586 diagram Methods 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 239000004065 semiconductor Substances 0.000 description 1
Landscapes
- Solid State Image Pick-Up Elements (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】この発明は、ビデオカメラやファ
クシミリ等に使用される固体撮像装置に関するものであ
る。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid-state image pickup device used for video cameras, facsimiles and the like.
【０００２】[0002]
【従来の技術】近年、固体撮像装置は半導体技術の急速
な進歩により高画素，低ノイズ化が進み、ビデオカメラ
やファクシミリ等に利用されるようになってきた。図３
は従来の固体撮像装置の構成を示す断面図で、同図にお
いて、１は光信号を信号電荷に変換する光電変換部でＰ
型シリコン基板５中にＮ- 型の不純物拡散層を形成した
ものである。２は光電変換部１で発生した信号電荷を転
送する電荷転送部で光電変換部１と同じくＰ型シリコン
基板５中にＮ- 型の不純物拡散層を形成したものであ
る。３は光電変換部１で発生した信号電荷を電荷転送部
２に読み出す読み出し部、４は電荷転送部２のゲート電
極と読み出し部３のゲート電極を兼ねたポリシリコンゲ
ート電極、５はＰ型シリコン基板である。2. Description of the Related Art In recent years, solid-state image pickup devices have come to be used in video cameras, facsimiles, etc. due to the progress of high pixel count and low noise due to the rapid progress of semiconductor technology. Figure 3
1 is a cross-sectional view showing the configuration of a conventional solid-state image pickup device. In FIG. 1, reference numeral 1 is a photoelectric conversion unit for converting an optical signal into a signal charge.
The N − type impurity diffusion layer is formed in the type silicon substrate 5. Reference numeral 2 denotes a charge transfer unit that transfers the signal charges generated in the photoelectric conversion unit 1, and has an N − -type impurity diffusion layer formed in the P-type silicon substrate 5 like the photoelectric conversion unit 1. Reference numeral 3 is a read-out portion for reading out the signal charges generated in the photoelectric conversion portion 1 to the charge transfer portion 2, reference numeral 4 is a polysilicon gate electrode that also serves as the gate electrode of the charge transfer portion 2 and the gate electrode of the read-out portion 3, and 5 is P-type silicon. The substrate.
【０００３】図４は図３のポリシリコンゲート電極４に
信号読み出し電圧を印加した時の信号電荷の流れを示す
図である。同図において、１０はポリシリコンゲート電
極に信号読み出し電圧を印加した時の信号電荷の流れる
方向を示す矢印、１１はポリシリコンゲート電極に信号
読み出し電圧を印加した時の等電位線を示す。以上のよ
うに構成された固体撮像装置についてその動作を説明す
る。FIG. 4 is a diagram showing the flow of signal charges when a signal read voltage is applied to the polysilicon gate electrode 4 of FIG. In the figure, 10 is an arrow showing the direction in which signal charges flow when a signal read voltage is applied to the polysilicon gate electrode, and 11 is an equipotential line when a signal read voltage is applied to the polysilicon gate electrode. The operation of the solid-state imaging device configured as described above will be described.
【０００４】まず、図３の光電変換部１に光信号が入射
することで信号電荷が発生する。次に、ポリシリコンゲ
ート電極４に電圧を印加することにより読み出し部３が
開いて光電変換部１から電荷転送部２へ信号電荷が読み
出される。その後は電荷転送部２によって信号電荷が順
次転送される。First, a signal charge is generated when an optical signal is incident on the photoelectric conversion section 1 of FIG. Next, by applying a voltage to the polysilicon gate electrode 4, the reading section 3 is opened and the signal charges are read from the photoelectric conversion section 1 to the charge transfer section 2. After that, the charge transfer section 2 sequentially transfers the signal charges.
【０００５】[0005]
【発明が解決しようとする課題】しかしながら、上記の
ような構成では図４に示すように、信号電荷読み出し時
に界面領域を使用するため、信号電荷が界面準位の影響
により転送の劣化を起こしたり、ノイズを発生させたり
するという問題点があった。また、読み出し部３の界面
領域に暗電流を発生させるため、この暗電流成分が光電
変換部１または電荷転送部２に入り画像として点キズや
縦線キズになるという問題点があった。However, in the above-mentioned structure, as shown in FIG. 4, since the interface region is used at the time of reading out the signal charge, the signal charge may deteriorate the transfer due to the influence of the interface level. However, there was a problem that noise was generated. Further, since a dark current is generated in the interface area of the reading section 3, this dark current component enters the photoelectric conversion section 1 or the charge transfer section 2 and causes a dot flaw or a vertical line flaw as an image.
【０００６】したがって、この発明の目的は、界面準位
の影響によって転送劣化やノイズおよび点キズ、縦線キ
ズ等の発生を防止することができる固体撮像装置を提供
するものである。Therefore, an object of the present invention is to provide a solid-state image pickup device capable of preventing transfer deterioration, noise and dot scratches, vertical line scratches and the like due to the influence of interface states.
【０００７】[0007]
【課題を解決するための手段】この発明の固体撮像装置
は、光信号を信号電荷に交換する光電変換部と、光電変
換部で発生した信号電荷を転送する電荷転送部と、光電
変換部から電荷転送部に信号を読み出す読み出し部とを
備えた固体撮像装置であって、読み出し部の界面領域お
よび界面領域の近傍を、光電変換部および電荷転送部と
逆型の高濃度不純物拡散層で形成するようにしている。A solid-state image pickup device according to the present invention comprises a photoelectric conversion part for exchanging an optical signal for a signal charge, a charge transfer part for transferring a signal charge generated in the photoelectric conversion part, and a photoelectric conversion part. A solid-state imaging device comprising: a read-out unit for reading out signals to a charge transfer unit, wherein an interface region of the read-out unit and the vicinity of the interface region are formed by a high-concentration impurity diffusion layer opposite to the photoelectric conversion unit and the charge transfer unit. I am trying to do it.
【０００８】[0008]
【作用】この発明の構成によれば、光電変換部で発生し
た信号電荷を電荷転送部に読み出す読み出し部の界面領
域およびその近傍が、光電変換部および電荷転送部と逆
型の高濃度不純物拡散層で構成されているので、光電変
換部と電荷転送部の間の読み出し部の幅を、ショートチ
ャンネル効果により電荷転送部の電位が読み出し部に影
響を与えるような寸法にすれば、読み出し部の界面領域
および界面領域近傍が界面準位の影響を受けず、基板と
同電位に固定され、信号電荷は読み出し部のバルク領域
を通過する。このため、読み出し部の界面領域を使用せ
ずに光電変換部から電荷転送部への信号電荷読み出しを
実現することができる。According to the structure of the present invention, the interface region of the reading section for reading out the signal charges generated in the photoelectric conversion section to the charge transfer section and its vicinity are the high-concentration impurity diffusions of the opposite type to the photoelectric conversion section and the charge transfer section. Since it is composed of layers, if the width of the readout section between the photoelectric conversion section and the charge transfer section is dimensioned such that the potential of the charge transfer section affects the readout section due to the short channel effect, The interface region and the vicinity of the interface region are not affected by the interface state and are fixed at the same potential as the substrate, and the signal charges pass through the bulk region of the reading section. Therefore, the signal charge can be read from the photoelectric conversion unit to the charge transfer unit without using the interface region of the read unit.
【０００９】[0009]
【実施例】以下この発明の実施例について図面を参照し
ながら説明する。図１は、この発明の実施例である固体
撮像装置の構成を示す断面図で、同図において、従来例
を示す図３と同符号のものは同じものを示す。この実施
例では、従来例の構成に対して、読み出し部３の界面領
域およびその近傍部が高濃度Ｐ型不純物拡散層６で形成
されている。この光電変換部１と電荷転送部２の間の読
み出し部３の幅は、ショートチャンネル効果により電荷
転送部２の電位で読み出し部３の電位が影響を受ける様
な寸法となっている。Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view showing the configuration of a solid-state image pickup device according to an embodiment of the present invention. In FIG. 1, the same reference numerals as those in FIG. In this embodiment, the interface region of the read section 3 and its vicinity are formed by the high-concentration P-type impurity diffusion layer 6 as compared with the configuration of the conventional example. The width of the read section 3 between the photoelectric conversion section 1 and the charge transfer section 2 is dimensioned so that the potential of the read section 3 is affected by the potential of the charge transfer section 2 due to the short channel effect.
【００１０】図２は、図１におけるポリシリコンゲート
電極４に信号読み出し電圧を印加した時の信号電荷の流
れを示す図で、同図において、７はポリシリコンゲート
電極４に信号読み出し電圧を印加した時の信号電荷の流
れる方向を示す矢印、８はポリシリコンゲート電極に信
号読み出し電圧を印加した時の等電位線を示す。実施例
の固体撮像装置は上記のように構成されているので、光
電変換部１に光信号が入射すると信号電荷が発生する。
この時、ポリシリコンゲート電極４に信号読み出し電圧
を印加すれば、電荷転送部２の電位が高くなってショー
トチャンネル効果が生じ、読み出し部３のバルク領域が
開いて光電変換部１から電荷転送部２へ信号電荷が読み
出される。その後は電荷転送部２によって信号電荷が順
次転送される。FIG. 2 is a diagram showing the flow of signal charges when a signal read voltage is applied to the polysilicon gate electrode 4 in FIG. 1. In FIG. 2, 7 is a signal read voltage applied to the polysilicon gate electrode 4. An arrow 8 indicates the direction in which the signal charge flows at the time, and 8 indicates an equipotential line when a signal read voltage is applied to the polysilicon gate electrode. Since the solid-state imaging device according to the embodiment is configured as described above, when an optical signal enters the photoelectric conversion unit 1, signal charge is generated.
At this time, if a signal read voltage is applied to the polysilicon gate electrode 4, the potential of the charge transfer unit 2 increases and a short channel effect occurs, and the bulk region of the read unit 3 opens and the photoelectric transfer unit 1 transfers the charge transfer unit. The signal charge is read to 2. After that, the charge transfer section 2 sequentially transfers the signal charges.
【００１１】上記したように、このような動作を行なう
固体撮像装置では、光電変換部１から電荷転送部２へ信
号電荷を読み出す時に、読み出し部３の界面領域および
界面領域近傍はポリシリコンゲート電極４の影響を受け
ずにＰ型シリコン基板５と同電位に固定されるので、信
号電荷は読み出し部３のバルク領域を通過することにな
る。As described above, in the solid-state image pickup device performing such an operation, when the signal charges are read from the photoelectric conversion unit 1 to the charge transfer unit 2, the polysilicon gate electrode is formed in the interface region of the readout unit 3 and in the vicinity of the interface region. Since the signal charges are fixed to the same potential as the P-type silicon substrate 5 without being affected by 4, the signal charges pass through the bulk region of the reading section 3.
【００１２】以上のようにこの実施例によれば、信号電
荷読み出し時に、読み出し部３の界面領域を使用するこ
となく光電変換部１から電荷転送部２への信号電荷読み
出しを実現することができるので、界面領域の影響によ
る転送劣化やノイズおよび点キズ、縦線キズが発生する
ことを防止することができる。尚、上記実施例では、光
電変換部１をＮ- 不純物拡散層としたが、光電変換部１
はＮ- 不純物拡散層に限定されるものではなく、光信号
を信号電荷に変換し蓄積する機能を有するものであれば
よい。例えば、ＰＮＰ構造の光電変換部を用いることも
できる。また、上記実施例では光電変換部１、電荷転送
部２、読み出し部３をＰ型シリコン基板５上に構成した
が、Ｐ型シリコン基板上に構成されたものに限定される
ものではなく、Ｎ型基板上に形成されたＰ型不純物層に
構成してもよい。As described above, according to this embodiment, when the signal charge is read, the signal charge can be read from the photoelectric conversion unit 1 to the charge transfer unit 2 without using the interface region of the reading unit 3. Therefore, it is possible to prevent transfer deterioration due to the influence of the interface region, noise, dot scratches, and vertical line scratches from occurring. In the above-mentioned embodiment, the photoelectric conversion part 1 is the N − impurity diffusion layer, but the photoelectric conversion part 1
Is not limited to the N − impurity diffusion layer, and may be any one having a function of converting an optical signal into a signal charge and storing the signal charge. For example, a photoelectric conversion part having a PNP structure can also be used. Further, although the photoelectric conversion unit 1, the charge transfer unit 2, and the reading unit 3 are formed on the P-type silicon substrate 5 in the above-described embodiment, the photoelectric conversion unit 1, the charge transfer unit 2, and the readout unit 3 are not limited to those formed on the P-type silicon substrate, and N You may comprise in the P type impurity layer formed on the mold substrate.
【００１３】[0013]
【発明の効果】この発明の固体撮像装置は、光電変換部
で発生した信号電荷を電荷転送部に読み出す読み出し部
の界面領域およびその近傍が、光電変換部および電荷転
送部と逆型の高濃度不純物拡散層で構成されているの
で、光電変換部と電荷転送部の間の読み出し部の幅を、
ショートチャンネル効果により電荷転送部の電位が読み
出し部に影響を与えるような寸法にすれば、読み出し部
の界面領域および界面領域近傍が界面準位の影響を受け
ず、基板と同電位に固定され、信号電荷は読み出し部の
バルク領域を通過する。このため、読み出し部の界面領
域を使用せずに光電変換部から電荷転送部への信号電荷
読み出しを実現することができ、界面領域の影響による
転送劣化やノイズおよび点キズ、縦線キズが発生するこ
とを防止することができる。According to the solid-state image pickup device of the present invention, the interface region of the readout unit for reading out the signal charges generated in the photoelectric conversion unit to the charge transfer unit and the vicinity thereof are high-concentration reverse to the photoelectric conversion unit and the charge transfer unit. Since it is composed of the impurity diffusion layer, the width of the reading section between the photoelectric conversion section and the charge transfer section is
If the dimension of the potential of the charge transfer portion influences the reading portion due to the short channel effect, the interface region of the reading portion and the vicinity of the interface region are not affected by the interface state and are fixed at the same potential as the substrate, The signal charge passes through the bulk region of the reading section. Therefore, the signal charge can be read from the photoelectric conversion unit to the charge transfer unit without using the interface region of the readout unit, and transfer deterioration due to the influence of the interface region, noise, dot scratches, and vertical line scratches occur. Can be prevented.
【図１】この発明の実施例である固体撮像装置の構成を
示す断面図である。FIG. 1 is a cross-sectional view showing a configuration of a solid-state imaging device that is an embodiment of the present invention.
【図２】実施例装置において読み出し電圧を印加した時
の信号電荷の流れを示す図である。FIG. 2 is a diagram showing a flow of signal charges when a read voltage is applied in the device of the embodiment.
【図３】従来の固体撮像装置の構成を示す断面図であ
る。FIG. 3 is a cross-sectional view showing the configuration of a conventional solid-state imaging device.
【図４】従来例装置において読み出し電圧を印加した時
の信号電荷の流れを示す図である。FIG. 4 is a diagram showing a flow of signal charges when a read voltage is applied in a conventional device.
１ 光電変換部 ２ 電荷転送部 ３ 読み出し部 ４ ポリシリコンゲート電極 ５ Ｐ型シリコン基板 ６ 高濃度Ｐ型不純物拡散層 ７ 信号電荷の流れる方向を示す矢印 ８ 等電位線 1 Photoelectric Conversion Section 2 Charge Transfer Section 3 Readout Section 4 Polysilicon Gate Electrode 5 P-type Silicon Substrate 6 High-concentration P-type Impurity Diffusion Layer 7 Arrows showing the direction of signal charge 8 Equipotential line
Claims (1)
と、前記光電変換部で発生した信号電荷を転送する電荷
転送部と、前記光電変換部から前記電荷転送部に信号を
読み出す読み出し部とを備えた固体撮像装置であって、 前記読み出し部の界面領域および界面領域の近傍を、前
記光電変換部および前記電荷転送部と逆型の高濃度不純
物拡散層で形成したことを特徴とする固体撮像装置。1. A photoelectric conversion unit for exchanging an optical signal for a signal charge, a charge transfer unit for transferring a signal charge generated in the photoelectric conversion unit, and a reading unit for reading a signal from the photoelectric conversion unit to the charge transfer unit. A solid-state imaging device comprising: a read-out portion, wherein an interface region of the read-out portion and the vicinity of the interface region are formed of a high-concentration impurity diffusion layer of an opposite type to the photoelectric conversion portion and the charge transfer portion. Solid-state imaging device.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4280004A JPH06132509A (en) | 1992-10-19 | 1992-10-19 | Solid-state image sensing device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4280004A JPH06132509A (en) | 1992-10-19 | 1992-10-19 | Solid-state image sensing device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH06132509A true JPH06132509A (en) | 1994-05-13 |
Family
ID=17618966
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP4280004A Pending JPH06132509A (en) | 1992-10-19 | 1992-10-19 | Solid-state image sensing device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH06132509A (en) |
-
1992
- 1992-10-19 JP JP4280004A patent/JPH06132509A/en active Pending
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